BIOMASS ALLOCATION IN LATE PENNSYLVANIAN COAL-SWAMP PLANTS

Carbon allocation to different tissues and organs of Late Pennsylvania n-aged coal-swamp plants was determined for the first time through stu dy of coal balls from the Calhoun coal of central Illinois. Coal balls are concretions that preserve the original peat fabric of the coal se am; they occur within the coal matrix and generally are permineralized with calcium carbonate. Coalified plant cell walls are preserved with in the mineral matrix of the coal ball, entombed within the calcium ca rbonate. Relative carbon allocation was determined by separation of th e mineral matrix and organic carbon. Carbon content was determined for replicates of tissues or organs of Psaronius tree ferns, Medullosa pt eridosperms, the lycopsid Sigillaria approximata, the small fern Botry opteris forensis, and ''whole peat''. Unit volume results for tissues and organs were normalized for trunk sections 45 cm in diameter and 1 m long. Psaronius tree ferns were significantly ''cheaper'' than all o ther plants due to the large mantle of aerenchymatous roots that made up the bulk of the trunk. Medullosans and small ferns were most ''expe nsive'', with the arborescent lycopsid in between. Relative expense of construction closely parallels the inferred ecological role of each p lant within ancient coal swamps, deduced from distributional patterns and indicators of habitat conditions. Tree ferns and lycopsids are col onists, medullosans are site occupying forms.